Portable paging receivers have become increasingly important to our more mobile society. Advances in battery technology play no small part in contributing to our societal mobility. As battery powered equipment, radios, and pagers came into more frequent use and were used for longer periods of time before returning to sites of fixed power distribution, battery power depletion became a problem. The advent of the rechargeable battery cell was one solution to the problem of battery power depletion. Correspondingly, battery powered equipment has had to accomodate both the conventional disposable battery cell and the rechargeable battery cell.
Initially, the rechargeable battery cell was removed from the portable electric equipment and placed into a separate battery charger located at the site of fixed electrical distribution. However, since the rechargeable battery must be manually removed from a piece of portable equipment and be manually placed into the battery charger, proper positive placement of the rechargeable battery into the battery charger became a recurrent problem. Also, the continued use of the portable electric equipment was lost while the rechargeable cell was being recharged outside of the equipment.
To alleviate this problem, charging circuits were built into the portable radio equipment itself. However, since both conventional disposable battery cells and rechargeable battery cells can be utilized to power the very same pieces of equipment, it is necessary to have the internal charging circuit distinguish between the rechargeable battery cell and the conventional disposable battery cell.
In one instance, an electrically conductive plate having an axially projecting tip was resistance welded to the flat end of the rechargeable battery cell (the anode). When the tip was present, the tip would engage the battery charging circuitry. When the tip was not present, as in the case of the conventional disposable battery cell, the charging circuits would not be engaged. Unfortunately, the resistance welding of this auxiliary tip had a corresponding cost that was not insubstantial.
In the past, this auxiliary terminal was installed on a large flat surface on the end of the battery cell (the anode). With this large surface and the entire battery jacket available for attachment of the welding electrode, attachment was easily performed using projection or resistance welding techniques. However, on the cathode end of the battery, the available welding area is small and the raised metal cathode button is effectively isolated, camouflaged and obscured by the insulating seal ring. Welding access to the cathode electrode of the battery cell is nearly impossible. This invention solves the problem by frictionally, mechanically locking a properly designed auxiliary charging terminal between the insulating seal ring of the cell and the raised cathode terminal of the battery cell.
This invention represents a significant advance over the prior design and over this technical field by providing an auxiliary battery charging terminal that may be easily attached to a conventional rechargeable battery cell without resorting to costly welding and bonding techniques.